Understanding of neuromuscular disease is founded on careful clinical observation, electrodiagnostic studies and pathology. This protocol has been carried out to learn more about established diseases, to characterize new diseases, to assess current methodologies and technologies and to refine old methods and develop new ones. Extensive studies of autonomic nerve function have been carried out in normal subjects, and patients with autonomic failure from either idiopathic orthostatic hypotension (IOH) or multiple system atrophy (MSA). It is possible to distinguish normals from patients on the basis of several parameters, but it has not been possible to separate the two groups of patients. Detailed studies have been carried out in patients with post-polio muscular atrophy (PPMA) syndrome. Methods included nerve conduction, repetitive stimulation, quantitative EMG and single fiber EMG. There were marked abnormalities of routine and single fiber EMG, but not much difference between patients with PPMA and patients with a past history of polio, but without PPMA.